Radio instrument



Dec. 19, 1933. c. R. BATZEL 1,940,342

RADIO INSTRUMENT Filed Oct 16, 1929 CHARLES R. BATZEL Patented Dec. 19, 1933 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates to radio receiving sets; and more particularly, to means for reducing the effect on such sets of what is commonly known as static.

The primary object of this invention is to producestructure that is commercially feasible and that will reduce static effects now so common in most radio receiving sets. The term static applies to disturbances set up in the air surrounding the radio set in the form of atoms of electricity,'which constantly beat upon the outer surfaces of radio instruments.

I have found by exhaustive experiment that the seat of practically all objectionable static eifects as relating to a radio set, resides in the coils and condensers.

Having determined the seat .of practically all static trouble, the problem then resolved itself into the elimination or reduction of these disturbances.

I conducted numerous experiments of ways and means for eliminating this static, particularly by the use of a vacuum. I found that it was necessary to use a very high vacuum, tested on a McLeod mercury gauge, which shows within one and one-half millimeters of an absolute vacuum. A vacuum of less than thirty inches failed to eliminate static.

My problem, then, was to provide an outer covering for the coils and condensers that would stand up under such a vacuum. This problem was materially simplified by the elimination of all other parts.

I found that an outer covering in the form of a tube of cylindrical contour would stand up under such a vacuum, and since it was only necessary to enclose the coils and condensers, a tube could be made to encase each separately.

Having decided on my type of vacuum condenser container my next problem was to provide means for carrying the leads and contact points from the vacuum formed, particularly that surrounding the condenser tubes, without danger of leakage. I found that the leads would have to be of a non-porous material-preferably platinum or tungsten. Since the condenser tube was surrounded by a vacuum, it became necessary to provide some means for rotating the sets of condenser plates relative to each other. This could be done by way of remote control, using any one of the well-known remote controls now' on the market, but I preferred to provide manually operable means for accomplishing this purpose, since a remote control would necessitate an extra motor and added cost.

Other objects will be disclosed in the specification and drawing forming a part of this application,

In the drawing:

Figure'l is a perspective view of a radio receiving set;

Figure 2 is a view partly in elevation, and partly in longitudinal section of a condenser forming an essential part of this invention;

Figure 3 is a vertical transverse section taken on the line 3-3 of Figure 2, but with the right hand end of the condenser proper shown in elevation and with part broken away;

Figure 4 is a fragmentary detail section of the condenser; and

Figure 5 is a fragmentary cross section illustrating the mounting of the condenser plates in framework which supports the condenser as a whole in an evacuated casing.

The reference character 1 designates a radio receiver of the usual type, including coils 2 enclosed in evacuated casings 3 suitably mounted on a base 4. The gang of condensers 5, 6 and 'I of the set is enclosed in a hermetically sealed and evacuated casing 8. The casing 8, of glass or other suitable insulating material, is frictionally supported at its opposite ends by resilient gripping members 9 and 10 having trunnions 11 and 12 suitably secured to the center thereof. The trunnions 11 and 12 are axially aligned and are rotatably mounted in bearings formed in the upper ends of standards 13 and 14 having their lower ends fixed to the base 4. The trunnion 11 projects through its bearing and has the usual graduated dial- 15 fixed thereto.

- The resilient gripping members 9 and 10 have their ends inturned toward each other and provided with friction pads 16 of rubber or any other suitable material. These pads 16 frictionally engage the opposite ends of the casing 8 and serve to rotate the said casing whenever the dial 15 is rotated in one direction or the other. The casing 8 has its axis concentric with the axis of the trunnions 11 and 12 and a frame designated generally by the reference character 17 is mounted within the casing 8 so as to support the relative rotatable elements of the condensers 5, 6 and '7 properly spaced apart from each other and from the wall of the casing 8.

The end walls 18 and 19 of the frame 17 have secured thereto substantially U-shaped spring members 20 provided at their free ends with friction pads 21 adapted to support the entire framework against rotation within the' casing 8.

The condensers 5, 6 and 7 are connected together to form a gang. The stator 22 has the plates P thereof suitably spaced apart along a shaft 23 which is mounted to rotate in conductor bearings 24 and 25 secured in the end walls 18 and 19 of the frame 17. The rotor of the gang has its plates P suitably spaced apart along and fixed to two of the rods 26, the opposite ends of which are secured in sleeves 27 and 28 of insulating material fixed tothe end walls 18 and 19. Four of these rods 26, shown in Figure 3, are used to connect the end walls 18 and 19 to each other; and to form, with said end walls, the frame 17.

The casing 8 is surrounded for the greater part of its periphery by an arcuate hood 29, the opposite ends of which are fixed to brackets 30 and 31 which extend laterally from a supporting block 32. Leads 33 connect the rotor plates of the condensers 5, 6 and 7 to contact terminals 34 suitably secured in proper position on the outer periphery of the casing 8. These terminals 34 are adapted to slide along the arcuate slip rings 35, 36 and 37 mounted in grooves suitably formed around the inner periphery of the hood 29. The slip rings are provided with the usual wire clamping screws 38, 39 and 40, the shanks of which extend through the hood and are adapted to be electrically connected to the wiring of the receiver set in the usual manner.

The stator 22 common to all three condensers is electrically connected to the end wall 19 of the frame 17 which is electrically connected as by a wire 41'-to a conducting button 42 slidably in contact with the arcuate slip ring 43 mounted on the hood 29 in the same manner as the slip rings 35, 36 and 37.

A clamping screw 44 extends through the hood 29 to be connected up to the wire 45 leading to ground. The shaft 23 has secured to the opposite ends thereof suitable weights 46 and 47 which maintain the stator 22 fixed in space during the rotation of the casing 8 by means of the dial 15 andthe elements connecting said dial to the casing. The casing 8 is evacuated as much as possible and sealed. It will be obvious from inspection of the drawing that when the dial 15 is rotated, the condenser plates will be adjusted relative to each other without in any way affecting the vacuum condition of the casing 8 in which the condenser elementsare mounted.

It is thought that the invention and numerous of its attendant advantages will be understood from the foregoing description and it is obvious that numerous changes may be made in the form,

construction and arrangement of the several parts In a variable condenser, a base plate, a pair of standards mounted thereon, an evacuated casing, clamping plates secured to the ends of said casing and having aligned trunnions journaled in said standards, means connected to one of said trunnions for rotating said clamping plates and casing, a condenser mounted within said casing and including a frame, means for fixing said frame to said casing, a set of condenser plates fixed to said frame, a shaft journaled to said frame, a second set of condenser plates fixed to said shaft and coacting with the first set, a pendulum fixed to said shaft for holding the second set fixed in space during the rotation of said casing, a hood fixed to said base plate concentric with said shaft, slip rings fixed to said hood, contacts slidable along said rings and electrically connected to the first named set of plates, another slip ring, means for electrically connecting the last named set of plates to the other ring, and means for grounding the last named ring.

- CHARLES R. BATZEL. 

